19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Which of the following processes is a non-spontaneous process?
The standard free energy change G is related to K (equilibrium constant) as
The enthalpy of vaporisation of a substance is 8400 J mol–1 and its boiling point is –173ºC. The entropy change for vaporisationis :
In an adiabatic expansion of ideal gas
When ice melts into water, entropy
The absolute enthalpy of neutralisation of the reaction: (g) (g) 2(aq) (l) MgO 2HCl MgCl H O → Will be (2005)
Entropy is a measure of
Which of the following statements is not correct?
Given that bond energies of H – H and Cl – Cl are 430 kJ mol–1 and 240 kJ mol–1 respectively and f H for HCl is-90 kJ mol–1 bond enthalpy of HCl is (2007)
Which law states that entropy of all pure crystalline solids is zero at absolute zero?
Thermodynamically, the most stable form of carbon
For a reaction: X → Y + Z absolute entropies are X = 120 JK–1 mol–1 Y = 213.8 JK–1 mol–1 and Z = 197.9 JK–1 mol–1. What will be the entropy change at 298 K and 1 atm?
Entropy of the universe is
Which one of the following is not always negative?
The correct thermodynamic conditions for the spontaneous reaction at all temperatures is (NEET-I 2016)
The standard enthalpies of formation of HCl(g), H (g) and Cl₂(g) are –92.2, 217.7 and 121.4 kJ mol-1 respectively. The bond dissociation energy of HCl is:
The molar heat capacity of water at constant pressure, C, is 75J K-1. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is. (2003)
For the reaction, 8 g 2 g 2 g l C H 5O 3CO 4H O → at constant temperature, H E is (2003)
Which of the following processes is irreversible?
When 0.5 g of sulphur is burnt to SO₂ 4.6 kJ of heat is liberated. What is the enthalpy of formation of sulphurdioxide?
The heat of formation of Fe O s is –824.2 kJ mol–1. ∆H for the reaction. 2Fe O s 4Fe s 3O g → is:
Internal energy is the sum of
In an isothermal expansion of an ideal gas
105. (∆U – ∆H) for the formation of NH₃ from N₂ and H₂ is :
Regarding the internal energy of the molecule, which of the following statement is correct?